Research On Airflow Characteristic Of Different SOFA Layouts With Wall Tangential Firing Combustion

SOFA(separated over firing air)is a kind of deep air-staging low NOx combustion technology,it requires not only to reduce the production of NOx greatly, but also to ensure the fuel burning out meanwhile.The paper adopt a supercritical wall tangential firing combustion pulverized coal boiler as research object, this boiler adopt separated over firing air technology, the cold modeling experiment use 3D-PDA system to measure and analyze SOFA airflow characteristic of different SOFA layouts, meanwhile, using heat bulb to measure and analyze the airflow velocity deviation in panel zone. The furnace combustion processes was also simulated to further study SOFA flow characteristic and flue gas temperature deviation of furnace outlet under different SOFA layouts.The cold modeling experiment results show that, 1. For SOFA with corner-tangential layout, after SOFA deflect 5°reversely, its airflow jet rigidity is weakened,its penetrating ability is weakened, velocity attenuation is faster and airflow diffusion is improved unconspicuously, so it's not beneficial to the mixing between SOFA flow and main air flow. When SOFA deflect 10°reversely, its jet rigidity is reinforced, its penetrating ability is enhanced and airflow diffusion is improved, therefore, it is beneficial to the mixing between SOFA flow and main air flow. for SOFA with wall-tangential layout, with the promotion of SOFA deflection angles, SOFA flow penetrating ability is enhanced and its diffusion is improved, it is in favor of the mixing between SOFA flow and main air flow. Compared with the SOFA wall-tangential layout, the SOFA airflow of SOFA with corner-tangential layout is beneficial to mix with main air flow. 2. For SOFA with corner-tangential layout, after SOFA deflect 5°reversely, the airflow velocity deviation in panel zone is reduced, however, after SOFA deflect 10°reversely, the airflow velocity deviation in panel zone is increased. For SOFA with wall-tangential layout, when SOFA deflect 5°and10°reversely, they all don't reduce the airflow velocity deviation.The simulation results show that, 1. For SOFA with corner-tangential layout, after SOFA deflect 5°reversely, its penetrating ability is not been enhanced, but when SOFA deflect 10°reversely, its penetrating ability is enhanced, so it is advantage of the mixing between SOFA flow and high tempreture flue gas. For SOFA with wall-tangential layout, with the promotion of SOFA deflection angles, the penetrating ability of SOFA flow is enhanced, it is beneficial to mix with high tempreture flue gas. Compared with the SOFA wall-tangential layout, the SOFA airflow of SOFA with corner-tangential layout is beneficial to mix with high tempreture flue gas. 2. For SOFA with corner-tangential layout, the SOFA flow acts with the rotational high tempreture flue gas strongly, it is beneficial to weaken the main gas flow rotation and decrease flue gas temperature deviation of furnace outlet. But for SOFA with wall-tangential layout, the increase of SOFA deflection angles don't reduce the decrease flue gas temperature deviation of furnace outlet.Through comparing and validating experiment results with simulation results,the consistency is well.